Recent reports suggested The Hangover star was fuming after a female fan crept onto the film set and took a pair of his underpants.
Cooper has dismissed the rumours, but admits one of the crew members wasn't happy when she heard the story - because she thought it implied she hadn't been doing her job properly.
Cooper tells ETOnline.com, "I don't think it's true... The (production assistant) at base camp was very offended by that because that meant that she wasn't doing her job. So, I don't think it's true."